which is a steady source of high-energy gamma rays in our own galaxy. By using mathematical equations that relate the duration of the flare to the size of the region emitting the bursts, Gaidos says ...

It does this by emitting a high energy electromagnetic wave called a gamma ray. Gamma radiation does not consist of particles but as short wavelength, high energy electromagnetic radiation emitted ...

This is because the particles or rays become more spread out. The thicker the substance, the more the radiation is absorbed. Alpha, beta and gamma radiations penetrate materials in different ways.